Abstract

The glands in the lining of the nose and throat produce mucus daily. This mucus is a thick, wet substance that moistens these areas, cleans the nasal membranes, humidifies the air, and helps to trap and destroy any foreign invaders, like bacteria, before they cause a problem. The cilia that line the nose assist in moving the mucus to the back of the throat, where it is unconsciously swallowed, together with saliva. The mucus is normally swallowed automatically, but the feeling of it accumulating in the throat and dripping down the back of it is referred to as "postnasal drip".